This Topex/Poseidon image of sea-surface heights was taken during a 10-day
collection cycle ending August 7, 2002. Sea-surface heights are a measure of how
much heat is stored in the ocean depths to influence future planetary climate
events. Since May 2001, there have been a series of warm Kelvin
waves—eastward-moving ocean waves that cross the equatorial Pacific in about
two months. A sizable one arrived at the South American coast last February,
raising the ocean temperature by 2 degrees Celsius (3.6 degrees Fahrenheit) and
triggering the National Oceanic and Atmospheric Administration’s forecast for a
mild El Niño in 2002. There was another wave in June, followed by the current
large pool of warm water in the tropical Pacific that is now moving toward the
coast of South America at a speed of 215 kilometers (134 miles) a day and will
arrive there in three to four weeks, raising ocean temperatures. Scientists will
continue to monitor the Pacific closely for further signs of El Niño formation
and intensity.

Over its ten-year lifespan, TOPEX/Poseidon has acquired continuous data on sea surface
height, wind speed, and wave height have given us a new understanding of how
ocean circulation affects climate. The satellite provides input for long-term
climate forecasting and prediction models. Topex/Poseidon produced the first
global views of seasonal current changes. It maps year-to-year changes in
upper-ocean heat storage. The satellite has improved our understanding of tides,
producing the world’s most precise global tidal maps and demystifying deep-ocean
tides and their effect on ocean circulation. It monitors global mean sea-level
changes, an effective indicator of the consequence of global temperature change.
Its data are input into atmospheric models for forecasting hurricane seasons and
individual storm severity. And the satellite has improved our knowledge of
Earth’s gravity field.